Art of refining rubber.



WIELIAM A. LAY; ELENCE, OT JAMAICF NEITEXAL RUBBER CQTMv NEW JERSEY.

resales,

Hr,- Drawing.

Specification of Letters 'Fatent.

Ain'zication filed Jul 1911,

1 iv v non To rn'r RCONTIT c-onrona'rzorr" or lntcnted iipr. S, 1913,,

To all whom it 1/1 (13 concur/2 Beit known that I, 'V t' IL-IJAM A. liaiv RENCE, a citizen of the United States. residing at No. ST Shelton avenue, Jamaica, borough of Queens, city and State or New York, have invented certain new and useful Improvements in the Art of Refining Rubber: and I do hereby declare the following to be a full. clear, and exact description of the invention. such as will enable'others skilled in the art to which it appertains to make and use the sauie. Y

My invention relates to certain new and useful improvements in the art of refining; crude rubber, and consists in bringing into intimate physical contact and potential chemical combination with the rubber the distillate obtained by the destructive distillation of wood in the presence of an allta line solution, as for instance, sodium hydrate, which the alkali I preferably employ. The mutual interaction of the dis-- tillate. the rubber and the alkaline solution ettect an improvement of the rubber distinctly greater than it' the alkaline solution were omitted, rendering the rubbei more nervy, more tough, more elastic, more stable, and less tacky.

The novelty of my present invention consists, 'efore, principally in the factnvhich I believe myself the first to discover, that by properly subjecting rubber, as hereinafter described, to the action of an alkaline reagent in solution in the presence of a solution comprising substantially the dis tillatc oi ained {roan the destructive dis tillation of wood, a beneficial effect. upon the rubber is produced of a quality dis tinctly greater than in case either solution is applied to the rubber without the other.

In carrying out my invention, I prefer for purposes of economy and convenience to use substantially the whole distillate including the tar, wnen its percentage is so small (say 5 percent.) as to be mechanically and coi'mnercially negligible as to use and value..and excluding it when it is mechanically objectionable or commercially valuable. I. may noivever, that lblS, ot

course, readily conceivable that, at the sacri' fice or partial sacrifice of the commercial advantage of using the cheap untractionated distillate, some other of its inert or substantially inert constituents than tar may be re moved or even that the constituents I111" nishing the active principle may be synthetitule tl For it tr. wise be Qnderstoo that in speci-t' in en'mloymcnt of the whole distillate l 0- with-mt the intent. of depriving 1iiyselt""-of the advantage of the-employmentof equirei lents, or of the right to remove 'oinornit i neutral constituents I will describethe employment of myink vention to the treatment of three ditto rent grades or conditions of rubbeig that is to" y (it) ruioer already extracted'from the wood, bark, or latex of ri'ibbenprot'lueiing plants, (2} rubber not yet extracted from 7 its vegetable sources, as For instance,""-r I her to be mechanically abstracteth'byr bins and pressure, from coinininuted plants-1 roots, barks, rhizomes and the like, and {3) rubber contained in the late); o-t nibb'e'r 'w, producing trees, vines or other sources "In practice, the process varies in'soirie paramlars for each of these three bonditions'lbf the rubber when thedistillate al'fone is So also, when together with the 'dist-illateiho an alkaline solution is employed as intb' present inventioi'i, there are further pre terred variations, required by the-addition of the alkaline solution, as will appear more fully from the following description. i

I. In case I am operating on rubber already extracted from the. Wood, bark; or, later of ruhber-prodncing plants, Iflfi'rst" comminute the rubber into small"part-icles, preferably by crping bet-ween rolls set.- as close togther as is practicable. I then place 5 this tlr her in a suitablevessel, preferably steamjacketed kettle With a cover capable of being closed and bolted at the top and tested to Withstand not lessv than 80 lbs. steam pressure to the square'ineh, with suit- I' able appliances forthe admissionand con trol of steam and water for charging 'a'ndt discharging. Into this kettle 'I place, for is ample, a charge of 450lbs. of the coin 1,1 0 minuted rubl and to treat tli'i'sl q' t y of rubber I use preferably n uprightflc lindrical kettle four feet 'dian'iete seven feet in depth. I the" 'refe a'l l'y' bring fortyfive pounosof 76 B f sodiiini mti hydrate into solution with i ti lf g allori .of cold water, making a two per ceinti'alltaline solution, and run this solution in upon the charge of rubber already in the'lte tt-le then run into the kettle two gallon's fof the mu distillate, distilled ref) fib i' hsl greenaud fresh cut, Wood-of'PinuaMaide I then promptly close-and bolt down the cover,

hermetically sealing it by a suitable gasket, and I admit steam to the steam jacket bring ing the pressure 'on the contents of the kettle up to preferably forty pounds by the gage, and hold it there preferably for one hour thereafter. At the end of one hour, I find, in practice, that an active principle of the distillate, assisted by the heat andpressure in the presence of the aqueous alkaline solution above described, has permeated mechanically and combined chemically with the solution and the rubber and has thereby produced the desired effect of increasing the nerve, elasticity, toughness and stability of the rubber, and at the same time decreasing its previously objectionable resinous content and stickiness to an extent tangibly greater than is the case where the alkaline solution is omitted and all other features of the processietained and carried out. At the end of the one hours boil above mentioned,

I prefer in practice to draw 0 the charge, preferably through avalved p pe not less than six inches in diameter, and preferably into a beater Washer suitably placed to re ceive the charge by gravity, in which beater washer by active maceration and agitation for preferabl half an hour in the presence of water pre erably hot, the rubber is practically cleared of the alkaline solution and of any detachable impurities existing in the original material, and is then ready to be skimmed ofl, sheeted out and dried in the ordinary manner. i

It should be here stated that I have found by repeated experiments that the active princlple of the distillate to which my invention by the aid of the added alkaline solution is indebted for its efficacy and usefulness, is readily volatile at 100 C. or 212 Fahr. and for't-hisreason' I' use a closed kettle, independent of the fact that the heat and Pres sure are also accessory to the chemical action of thefdistillate and the alkaline solution upon the rubber.

2. In case I am operating on rubber not yet extracted from its vegetable sources as,

for instance, on comminuted plants, roots,

barks, rhizomes, etc., containing rubber, I find that during the process otextracting the rubber by the mechanical means of rub bing and pressure, whatever means are used of 'sufiicient force to extract the rubber, are

however, double the proportion of distillate in proportion to the rubber present, as

formulated in the heat and pressureprocess above described, to make up forany distillate rendered inoperative by the presence of the ivoody matter of the raw unextracted material, and at the end of the process of extraction I find the rubber; decidedly improved in quality by the intimate contact of the distillate with the rubber accom plished by the mechanical means of rubbing and pressure While in the presence of Water. But I, also find, in accordance with my present invention, that if I add at the beginning of the extractive operation an aikaline solution to the charge of un-extracted rubber material, Water, and distillate already in the extractor, I obtain an addi tional chemical reaction which results in a decided improvement in the rubber over and above the in'iproxement resulting from the use of the distillate without the presence of the alkaline solution. In my present process, therefore, 'I add preferably sodium hydrate to the water used in the mechanical process of extraction in the proportion of one pound of about 76 Baum commercial sodium hydrate to each ten pounds of rubber contained in the charge under extraction. The large quantity of water required in the extraction of rubber from its vegetable sources by mechanical means (except in the treatment of latex) amply provides Sufficient Water to bring the sodium hydrate into proper solution, and the maceration and agitation of the process of extraction prorjiui s til intimate and p t longed contact of the alkaiiue solution with the rubber, so that at the end of the extraotive process the desired combination or iutor-action of the distillate and the alkaline solution with the rubber is complete, and thefutfthertreatmhnt of the rubber is carried out, in the ordihary manner.

in case I am operating on the rubber contained in the latex of rubber producing trees, vines or other sources, I find this material specially amenable to the action of chemical reagents by reason of the fact that the particles of rubber existing in emulsionin the latex are exceedingly small and mobile in the semi-liquid latex, and, therefore, under the influence of the active principles of certain'substances readily form a new arrangement of molecules(polymerization) by which transposition the physical properties of the rubber are changed Without changing its chemical composition. In

operating on rubber latex, therefore, for

the purpose of bringing to bear upon the rubber the polyn'ieriziner action of the distillate obtained by the desructive distillation of wood combined with an alkaline solution, it is.onl v necessary to bearin mind the normal percentage of rubber in the pa r :ilui\'0 the etl'ect of either reagent ticular sort of latex to be treated which percentage is already and practically well known to the 0 erator by his irevious operative results in weight of ru ber from a given weight of latex. I then proceed to carry out my invention, in its application to latex, by first stirring into and therughly mixing with the semi-liquid latex in the preferred proportion of 25 c. c.--or about one-fifth of a gill-of the distillate to each pound of dr rubber pertaining to the latex under treatment. The chemical coinosition of the distillate obtained by the destructive distillation of wood renders it necessarily a valuable assistant to the coagulation of the latex as well as an agent in the improvement of the rubber, but a still further improvement in the rubber is inevitable if a preferred and proper alkaline soluiioii is added romptly in succession to the application 0 the distillate to the latex, the combination of the distillate and the alkaline solution producing a decidedly iiiri'eusetl improvement of the rubber over and applied without the other as noted above in the case of rubber already extracted, but with an added advantage over that, owing to the (act that in the latex the rubber is held in emulsion in very minute and plastic particles, peculiarly amenable to chemical ren 'euts and resulting pol nieric transposition. This preferred altaline solution I lllltl in a five per cent. aqueous solution of sodium hydrate (NaOH). I prefer it for this purpose to potassium hydrate (KOH) or to any other alkaline reagent known to me, because in my experience I have found its eil'ect upon ru her to be at least as good as any other alkali, and its cost in extensive operations considerably less. Irompt-ly following the ap cation of the distillate to the latex I adt, therefore, and thoroughly stir and mix in, a preferred five per cent. aqueous solution of sodium h drate in the roportion of one pound 0 sodium hydrate, contained in the five per cent. solution, to twenty )ounds of rubber present in the latex, the ru )her figured as bone dry. The rubber is then ready, within half an laair, to be separated from the watery portion of the latex by any of the ordinary ittethods,-boiling, drying and smoking over alm-nut lli'e, open-air evaporation in flat pans, or by mechanical means, as, for iiistance by my own cone process (U. S. intent dated May 24th, 1004, #700,450), or y any other method which may be found la-st adapted to the particular variety of latex am or treatment. a

I have now described various methods and forms of apparatus by which the distillate il)lllln(!(l from the destructive distillation of description and roin the appended c aims.

Havin thus described my invention what I 0 mm is:

1. The method of improving rubber,

:iich consists in subjecting it to the action of an alkaline reagent in solution, in the presence of the distillate obtained by the destructive distillation of woody matter; substantially as described.

2. The method of improving rubber.

which consists in subjecting it to the action of caustic alkali in solution, in the presence of the distillate obtained by the destructive distillation of woody matter; substantially as described.

3. The method of improving rubber, which consists in subjecting it to the action of sodium hydrate in solution, in the presence of the distillate obtained by the destructive distillation of woody matter; siibstantially as described.

4. The method of improving rubber, which consists in bringing it into intimate physical contact and potential chemical combination with an alkaline reagent in sof lution, in the presence of the constituents, active with the alkaline reagent in the production of the results set forth, of the dis tillate obtained by the destructive distillation of woody matter; substantially as described.

5. The method of improving rubber, which consists in bringing it into intimate physical contact and potential chemical combination with caustic alkali in solution, in the presence of the constituents, active with the caustic alkali in the production of the results set forth, of the distillate obtained by the destructive distillation of woody matter; Substantially as described.

(I. The method of improving rubber, which consists in bringing it into intimate physical contact and potential chemical combination with sodium hydrate in solution, in the presence of the constituents. active with the sodium hydrate in the protluction of the results set forth, of the distillate obtained by ,the destructive distillation of woody matter; substantially as described.

In testimony whereof I allix my signature, in presence 0 two witnesses.

WILLIAM A. LAWRENCE.

Witnesses:

ll. K. (lltANDlN, Joim 0. Peanut.

Copies of this patent may be obtained for live cents each. by addressing the "Commissioner of Patents.

Wnshlngton, I). C."

lit

llll

lilt 

